Computation of electric field inside substations with boundary element methods and adaptive cross approximation

Power system substations and HV power lines are sources of electric and magnetic fields of industrial frequency. Guidelines for permissible electric and magnetic field strengths regarding human exposure and electromagnetic compatibility (EMC) are provided by standards. In this paper a novel method for calculating 3D electric field near power system facilities is presented. Computation procedure is based on integral equations and boundary element methods. The influence of polynomial order of functions used to approximate the unknown linear charge densities over the elements is tested for constant, linear and cubic spline functions. Due to a complex geometry of substations, a large system of equations needs to be solved to find the unknown charge densities over the elements of the model. In order to reduce computational efforts adaptive cross approximation (ACA) is employed. The results of computation are in a good agreement with measurements.